This invention relates to manually-operated reciprocating fluid pumps such as pump-type trigger sprayers.
A trigger sprayer typically includes a dispenser body, a closure cap connected to the dispenser body for securing the trigger sprayer to the neck of a container (or bottle), a dip tube depending from the dispenser body and configured for extending through a mouth (i.e., opening) in the neck of the bottle, and a gasket (or bottle seal) for preventing leakage between the closure cap and the mouth of the container when the closure cap closes the mouth of the container.
The dispenser body has a manually operated pump which draws liquid up the dip tube from the bottle and dispenses it through a nozzle via a liquid flow path in the dispenser body. A priming check valve within the liquid flow path and upstream of the pump permits fluid flow from the container to the pump, but checks fluid flow from the pump back to the container. Another check valve within the liquid flow path and downstream of the pump permits fluid flow from the pump to the nozzle, but checks fluid flow from the nozzle to the pump.
A concern associated with such a trigger sprayer is the cost of manufacture. A typical trigger sprayer is of relatively low cost. However, trigger sprayers with more pieces generally cost slightly more to produce than trigger sprayers with fewer pieces. Millions of trigger sprayers are sold each year for use in dispensing a wide variety of products. Because of the large volumes sold, a savings of even one cent per trigger sprayer is significant.
To reduce the number of trigger sprayer pieces, the closure cap and bottle seal of some conventional trigger sprayers are molded as integral portions of a housing of the trigger sprayer and are made of the same rigid material as the sprayer housing. Because the integral closure cap cannot rotate relative to the trigger sprayer housing, the skirt of the cap does not have a threaded inner surface for engaging a thread on the neck of the bottle. Rather, two diametrically opposite lugs extend radially inwardly from the skirt of the cap and are configured for a snap fit engagement with two diametrically opposite bayonet provisions on the neck of the bottle. The bottle seal of such sprayer is shaped to sealingly engage an inner surface (e.g., inner circumference) of the mouth of the bottle.
A concern with such bayonet-type bottle connection is that the closure cap tends to rock on the bayonet provisions of the bottle. This rocking may result in the bottle seal becoming unsealed from the mouth of the bottle thereby allowing inadvertent leakage of the liquid contents of the bottle between the bottle seal and bottle.
Another concern is that bottles used with trigger sprayers having generally rigid, integral seals are generally more costly to manufacture than bottles used with resilient elastomeric gaskets. The inner circumferential surface of the neck of such a bottle must be made with relatively close tolerances because the generally rigid seal does not readily conform to the shape of this surface. The requirement of close tolerances increases the cost of manufacturing the bottle.